Vibration of vehicle-bridge coupling system with measured correlated road surface roughness

Wanshui Han,Sujing Yuan,Lin Ma 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.2

The present study investigated the effect of the correlation of the measured road roughness profiles corresponding to the left and right wheels of a vehicle on the vibration of a vehicle-bridge couplingsystem. Four sets of road roughness profiles were measured by a laser road-testing vehicle. A correlationanalysis was carried out on the four roughness samples, and two samples with the strongest correlation andweakest correlation were selected for the power spectral density, autocorrelation and cross-correlation analyses. The scenario of a three-axle truck moving across a rigid-frame arch bridge was used as an example. The two selected road roughness profiles were used as inputs to the vehicle-bridge coupling system. Three different input modes were adopted in the numerical analysis: (1) using the measured road roughness profile of the left wheel for the input of both wheels in the numerical simulation; (2) using the measured road roughness profile of the right wheel for both wheels; and (3) using the measured roadroughness profiles corresponding to left and right wheels for the input corresponding to the vehicle‟s left and right wheels, respectively. The influence of the three input modes on the vibration of the vehicle-bridge system was analyzed and compared in detail. The results show that the correlation of the road roughness profiles corresponding to left and right wheels and the selected roughness input mode both have a significant influence on the vibration of the vehicle-bridge coupling system.

Dynamic analysis of long-span cable-stayed bridges under wind and traffic using aerodynamic coefficients considering aerodynamic interference

Wanshui Han,Huanju Liu,Jun Wu,Yangguang Yuan,Airong Chen 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.24 No.5

The aerodynamic characteristics of vehicles are critical to assess vehicle safety and passenger comfort for vehicles running on long span bridges in a windy environment. However, in previous wind–vehicle–bridge (WVB) system analysis, the aerodynamic interference between the vehicle and the bridge was seldom considered, which will result in changing aerodynamic coefficients. In this study, the aerodynamic coefficients of a high-sided truck on the ground (ground case) and a typical bridge deck (bridge deck case) are determined in a wind tunnel. The effects of existent structures including the bridge deck and bridge accessories on the high-sided vehicle’s aerodynamic characteristics are investigated. A three-dimensional analytical framework of a fully coupled WVB system is then established based on the finite element method. By inputting the aerodynamic coefficients of both cases into the WVB system separately, the vehicle safety and passenger comfort are assessed, and the critical accidental wind speed for the truck on the bridge in a windy environment is derived. The differences in the bridge response between the windward case and the leeward case are also compared. The results show that the bridge deck and the accessories play a positive role in ensuring vehicle safety and improving passenger comfort, and the influence of aerodynamic interference on the response of the bridge is weak.

Nonlinear dynamic performance of long-span cable-stayed bridge under traffic and wind

Wanshui Han,Lin Ma,C.S. Cai,Suren Chen,Jun Wu 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.2

Long-span cable-stayed bridges exhibit some features which are more critical than typical longspan bridges such as geometric and aerodynamic nonlinearities, higher probability of the presence ofmultiple vehicles on the bridge, and more significant influence of wind loads acting on the ultra high pylonand super long cables. A three-dimensional nonlinear fully-coupled analytical model is developed in thisstudy to improve the dynamic performance prediction of long cable-stayed bridges under combined trafficand wind loads. The modified spectral representation method is introduced to simulate the fluctuating windfield of all the components of the whole bridge simultaneously with high accuracy and efficiency. Then, theaerostatic and aerodynamic wind forces acting on the whole bridge including the bridge deck, pylon, cablesand even piers are all derived. The cellular automation method is applied to simulate the stochastic trafficflow which can reflect the real traffic properties on the long span bridge such as lane changing, acceleration,or deceleration. The dynamic interaction between vehicles and the bridge depends on both the geometricaland mechanical relationships between the wheels of vehicles and the contact points on the bridge deck. Nonlinear properties such as geometric nonlinearity and aerodynamic nonlinearity are fully considered. Theequations of motion of the coupled wind-traffic-bridge system are derived and solved with a nonlinearseparate iteration method which can considerably improve the calculation efficiency. A long cable-stayedbridge, Sutong Bridge across the Yangze River in China, is selected as a numerical example to demonstratethe dynamic interaction of the coupled system. The influences of the whole bridge wind field as well as thegeometric and aerodynamic nonlinearities on the responses of the wind-traffic-bridge system are discussed.

Nonlinear dynamic performance of long-span cable-stayed bridge under traffic and wind

Han, Wanshui,Ma, Lin,Cai, C.S.,Chen, Suren,Wu, Jun Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.20 No.2

Long-span cable-stayed bridges exhibit some features which are more critical than typical long span bridges such as geometric and aerodynamic nonlinearities, higher probability of the presence of multiple vehicles on the bridge, and more significant influence of wind loads acting on the ultra high pylon and super long cables. A three-dimensional nonlinear fully-coupled analytical model is developed in this study to improve the dynamic performance prediction of long cable-stayed bridges under combined traffic and wind loads. The modified spectral representation method is introduced to simulate the fluctuating wind field of all the components of the whole bridge simultaneously with high accuracy and efficiency. Then, the aerostatic and aerodynamic wind forces acting on the whole bridge including the bridge deck, pylon, cables and even piers are all derived. The cellular automation method is applied to simulate the stochastic traffic flow which can reflect the real traffic properties on the long span bridge such as lane changing, acceleration, or deceleration. The dynamic interaction between vehicles and the bridge depends on both the geometrical and mechanical relationships between the wheels of vehicles and the contact points on the bridge deck. Nonlinear properties such as geometric nonlinearity and aerodynamic nonlinearity are fully considered. The equations of motion of the coupled wind-traffic-bridge system are derived and solved with a nonlinear separate iteration method which can considerably improve the calculation efficiency. A long cable-stayed bridge, Sutong Bridge across the Yangze River in China, is selected as a numerical example to demonstrate the dynamic interaction of the coupled system. The influences of the whole bridge wind field as well as the geometric and aerodynamic nonlinearities on the responses of the wind-traffic-bridge system are discussed.

Dynamic analysis of long-span cable-stayed bridges under wind and traffic using aerodynamic coefficients considering aerodynamic interference

Han, Wanshui,Liu, Huanju,Wu, Jun,Yuan, Yangguang,Chen, Airong Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.5

The aerodynamic characteristics of vehicles are critical to assess vehicle safety and passenger comfort for vehicles running on long span bridges in a windy environment. However, in previous wind-vehicle-bridge (WVB) system analysis, the aerodynamic interference between the vehicle and the bridge was seldom considered, which will result in changing aerodynamic coefficients. In this study, the aerodynamic coefficients of a high-sided truck on the ground (ground case) and a typical bridge deck (bridge deck case) are determined in a wind tunnel. The effects of existent structures including the bridge deck and bridge accessories on the high-sided vehicle's aerodynamic characteristics are investigated. A three-dimensional analytical framework of a fully coupled WVB system is then established based on the finite element method. By inputting the aerodynamic coefficients of both cases into the WVB system separately, the vehicle safety and passenger comfort are assessed, and the critical accidental wind speed for the truck on the bridge in a windy environment is derived. The differences in the bridge response between the windward case and the leeward case are also compared. The results show that the bridge deck and the accessories play a positive role in ensuring vehicle safety and improving passenger comfort, and the influence of aerodynamic interference on the response of the bridge is weak.

Vibration of vehicle-bridge coupling system with measured correlated road surface roughness

Han, Wanshui,Yuan, Sujing,Ma, Lin Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.2

The present study investigated the effect of the correlation of the measured road roughness profiles corresponding to the left and right wheels of a vehicle on the vibration of a vehicle-bridge coupling system. Four sets of road roughness profiles were measured by a laser road-testing vehicle. A correlation analysis was carried out on the four roughness samples, and two samples with the strongest correlation and weakest correlation were selected for the power spectral density, autocorrelation and cross-correlation analyses. The scenario of a three-axle truck moving across a rigid-frame arch bridge was used as an example. The two selected road roughness profiles were used as inputs to the vehicle-bridge coupling system. Three different input modes were adopted in the numerical analysis: (1) using the measured road roughness profile of the left wheel for the input of both wheels in the numerical simulation; (2) using the measured road roughness profile of the right wheel for both wheels; and (3) using the measured road roughness profiles corresponding to left and right wheels for the input corresponding to the vehicle's left and right wheels, respectively. The influence of the three input modes on the vibration of the vehicle-bridge system was analyzed and compared in detail. The results show that the correlation of the road roughness profiles corresponding to left and right wheels and the selected roughness input mode both have a significant influence on the vibration of the vehicle-bridge coupling system.

Transient aerodynamic forces of a vehicle passing through a bridge tower`s wake region in crosswind environment

Lin Ma,Dajun Zhou,Wanshui Han,Jun Wu,Jianxin Liu 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.22 No.2

Super long-span bridges provide people with great convenience, but they also bring traffic safety problems caused by strong wind owing to their high decks. In this paper, the large eddy simulation together with dynamic mesh technology in computational fluid dynamics (CFD) is used to explore the mechanism of a moving vehicle`s transient aerodynamic force in crosswind, the regularity and mechanism of the vehicle`s aerodynamic forces when it passes through a bridge tower`s wake zone in crosswind. By comparing the calculated results and those from wind tunnel tests, the reliability of the methods used in the paper is verified on a moving vehicle`s aerodynamic forces in a bridge tower`s wake region. A vehicle`s aerodynamic force coefficient decreases sharply when it enters into the wake region, and reaches its minimum on the leeward of the bridge tower where exists a backflow region. When a vehicle moves on the outermost lane on the windward direction and just passes through the backflow region, it will suffer from negative lateral aerodynamic force and yaw moment in the bridge tower`s wake zone. And the vehicle`s passing ruins the original vortex structure there, resulting in that the lateral wind on the right side of the bridge tower does not change its direction but directly impact on the vehicle`s windward. So when the vehicle leaves from the backflow region, it will suffer stronger aerodynamic than that borne by the vehicle when it just enters into the region. Other cases of vehicle moving on different lane and different directions were also discussed thoroughly. The results show that the vehicle`s pneumatic safety performance is evidently better than that of a vehicle on the outermost lane on the windward.

Transient aerodynamic forces of a vehicle passing through a bridge tower's wake region in crosswind environment

Ma, Lin,Zhou, Dajun,Han, Wanshui,Wu, Jun,Liu, Jianxin Techno-Press 2016 Wind and Structures, An International Journal (WAS Vol.22 No.2

Super long-span bridges provide people with great convenience, but they also bring traffic safety problems caused by strong wind owing to their high decks. In this paper, the large eddy simulation together with dynamic mesh technology in computational fluid dynamics (CFD) is used to explore the mechanism of a moving vehicle's transient aerodynamic force in crosswind, the regularity and mechanism of the vehicle's aerodynamic forces when it passes through a bridge tower's wake zone in crosswind. By comparing the calculated results and those from wind tunnel tests, the reliability of the methods used in the paper is verified on a moving vehicle's aerodynamic forces in a bridge tower's wake region. A vehicle's aerodynamic force coefficient decreases sharply when it enters into the wake region, and reaches its minimum on the leeward of the bridge tower where exists a backflow region. When a vehicle moves on the outermost lane on the windward direction and just passes through the backflow region, it will suffer from negative lateral aerodynamic force and yaw moment in the bridge tower's wake zone. And the vehicle's passing ruins the original vortex structure there, resulting in that the lateral wind on the right side of the bridge tower does not change its direction but directly impact on the vehicle's windward. So when the vehicle leaves from the backflow region, it will suffer stronger aerodynamic than that borne by the vehicle when it just enters into the region. Other cases of vehicle moving on different lane and different directions were also discussed thoroughly. The results show that the vehicle's pneumatic safety performance is evidently better than that of a vehicle on the outermost lane on the windward.